Routing (electronic design automation)

Network packet

Internet Protocol

Embedded system

User Datagram Protocol

Operating system

Retransmission

The Internet

Communications protocol

Computer science

Protocol (science)

Distributed computing

Protocol design

Internet protocol suite

Computer network

Alternative medicine

Multicast

Routing protocol

Reliable multicast

Internet Protocol Control Protocol

Unicast

Resource Reservation Protocol

Medicine

Redundancy (engineering)

Protocol Independent Multicast

Pathology

IEEE Transactions on Industrial Informatics

Reliable packet delivery within stringent delayconstraints is of paramount importance to mission-critical computer applications with hard real-time constraints.Because retransmission and coding techniques counteract the delay requirements, reliability may be achieved through replication over multiple fail-independent paths.Existing solutions, such as the parallel redundancy protocol (PRP), replicate all packets at the MAC layer over parallel paths.PRP works best in local area networks.However, it is not viable for IP networks that are a key element of emerging mission-critical systems.This limitation, coupled with diagnostic inability and lack of security, renders PRP unsuitable for reliable data-delivery in these IP networks.To address this issue, we present a transport-layer solution: the IP parallel redundancy protocol (iPRP).Designing iPRP poses non-trivial challenges in the form of selective packetreplication, soft-state and multicast support.iPRP replicates only time-critical unicast or multicast UDP traffic.iPRP requires no modifications to the existing monitoring application, end-device operating system or to the intermediate network devices.It only requires a simple software installation on the end-devices.iPRP has a set of diagnostic tools for network debugging.With our implementation of iPRP in Linux, we show that iPRP supports multiple flows with minimal processing-and-delay overhead.It is being installed in our campus smart-grid network and is publicly available.

iPRP—The Parallel Redundancy Protocol for IP Networks: Protocol Design and Operation